Verfahren zur Überwachung einer elektrohydraulischen Fahrzeugbremsanlage

摘要

Indications of the enrichment of brake fluid with air are obtained from a comparison of the volume uptake of the wheel brakes at a specific wheel brake pressure with an evaluation threshold in a P/V diagram. The volume uptake is determined by the elasticity within the wheel brake and also by the aeration play that is present. To obtain a statement relating to the air charge, an estimation of the actual aeration play is first made, taking three areas into consideration. If there is a large amount of aeration play, no monitoring takes place and the method aims to reduce said play by an active aeration play limitation. If there is normal aeration play, an upper evaluation threshold is taken as a basis, which assumes the aeration play lies at the upper end of the normal range. If said evaluation limit is exceeded, a warning is triggered. If the aeration play lies at the lower limit of the normal range, a lower evaluation threshold is applied, although a warning is only triggered if this situation occurs several times in succession.